1. Field of the Invention
The present invention relates to a liquid ejection head and a method of manufacturing the same. More particularly, the present invention relates to arrangements of flying leads.
2. Description of the Related Art
Known typical electric connection systems for connecting one or more than one substrates having energy generating elements and an electric wiring member having flying leads include single point bonding systems and gang bonding systems.
With single-point bonding systems, a bonding operation is conducted individually on each flying lead, while checking the bonding position for the flying lead. Such bonding systems require preparatory operations including forming stud bumps and leveling before ultimately executing the bonding operations and the apparatus to be used for such bonding operations represents a complex configuration. The processing tact for such an apparatus depends on the number of flying leads. Since ultimate bonding operations are conducted by using ultrasonic waves, the bonding strength tends to be low.
With gang bonding systems, on the other hand, the connection pads on one or more than one substrates having energy generating elements are plated with gold or a gold-tin alloy and all the flying leads are crimped to the respective connection pads by applying heat and pressure so as to collectively bond them to the connection pads. Thus, the stress generated in the connection pads is suppressed to a low level and a high bonding strength can be achieved. Since all the flying leads are collectively bonded by means of a broad bonding tool, the flying leads can be correctly positioned with ease in a transversal direction (in the direction in which they are aligned). As a result, the apparatus to be used for gang bonding represents a relatively simple configuration. Since the time required for the bonding operation is substantially constant regardless of the number of flying leads, the processing tact for such an apparatus does not depend on the number of flying leads and hence the processing tact, the conditions on the processing steps and other factors can be selected and set with a high degree of freedom. Japanese Patent Application Laid-Open No. 2005-41158 describes a gang bonding system.
FIG. 10A of the accompanying drawings schematically illustrates flying leads that are electrically connected to so many connection pads of a substrate by means of a gag bonding system. A plurality of connection pads 3 are arranged on a substrate 1 having energy generating elements and the flying leads 2 of an electrical wiring member as many as the connection pads 3 are collectively aligned with the respective connection pads 3. Subsequently, the flying leads 2 are collectively bonded to the respective connection pads 3 by means of a bonding tool 6 having a width greater than the total width of the flying leads 2 (see FIG. 10C). As a result, the flying leads 2 represent traces 19 of thermal crimping.
Generally, a plurality of substrates is juxtaposed as illustrated in FIG. 10B and the individual substrates 1a, 1b are bonded in advance to an ink-supply and holding member (or an ink-supply assisting member) H1500 by means of an adhesive agent 10 or the like as illustrated in FIG. 10C. However, the top surfaces of the substrates 1a, 1b can hardly be made flush with each other for a number of reasons such as variance of the thickness of the adhesive agent 10 and inclination of the top surface of the ink-supply and holding member H1500. Then, a gang bonding operation can be executed only with difficulty in a state as illustrated in FIG. 10C. For this reason, the use of a dedicated bonding apparatus may be conceivable for gang bonding. More specifically, a plurality of substrates is aligned by means of a dedicated gang bonding apparatus and then a gang bonding operation is executed. Thereafter, the plurality of substrates is collectively bonded to an ink-supply and holding member along with an electrical wiring member. In this operation, the plurality of substrates and the electrical wiring member are received from the gang bonding apparatus by means of a dedicated finger and delivered to the ink-supply and holding member.
However, when using a dedicated gang bonding apparatus as described above, the substrates can move relative to each other so as to be displaced from each other in directions out of the plane that is supposed to be defined by the top surfaces of the substrates. Then, the plurality of substrates cannot be found on a single plane as a whole. Thus, the plurality of substrates cannot be placed in position so as to be held in parallel with the top surface (bonding surface) of the ink-supply and holding member to make the operation of bonding the substrates to the ink-supply and holding member a difficult one.